Selection of Ampicillin-Resistant Transformants: Isolates colonies of E. coli carrying bla-expressing plasmids on LB Lennox (1.0% Tryptone, 0.5% Yeast Extract, 0.5% NaCl, 1.5% Agar) with 100 µg/mL ampicillin.

Colony Screening After Cloning: Enables post-ligation/transformation screening of E. coli colonies for inserts via colony PCR or restriction analysis.

Streaking for Single Colonies: Used to streak and isolate single E. coli colonies from transformations or glycerol stocks under ampicillin selection.

Blue-White Screening (with X-gal/IPTG): Supports lacZ α-complementation on ampicillin plates when supplemented with X-gal and IPTG.

CFU Enumeration and Transformation Efficiency: Quantifies colony-forming units of ampicillin-resistant E. coli to assess cloning and transformation performance.

Plasmid Maintenance Under Selection: Maintains plasmid-bearing E. coli cultures by selecting for beta-lactamase-mediated ampicillin resistance.

Colony Picking for Downstream Workflows: Provides source colonies for miniprep, sequencing, subcloning, and expression in E. coli.

Library Propagation: Supports maintenance and expansion of plasmid libraries (e.g., genomic or cDNA) in E. coli with ampicillin selection.